1. Field of the Invention
This invention relates to an intermittent driving system which is suitable for a vehicle security apparatus.
2. Description of Related Art
Recently, a wide variety of electric devices include microcomputers having CPU and peripheral circuits mounted on one large integrated circuit. In order to reduce power consumption of the electric devices, the microcomputer has HALT mode or STOP mode which is a mode for reducing amount of electric consumption. The HALT mode is the mode for working only an oscillator of the microcomputer, and deactivating other internal circuits of the microcomputer. The STOP mode is the mode for deactivating the internal circuits including the oscillator of the microcomputer. Even when the microcomputer is deactivated, the electric power is provided to the microcomputer. Therefore electric power is consumed by a leak current and so on in HALT mode or STOP mode.
Therefore the leak current has been heretofore reduced by controlling the electric power provided to the microcomputer. An example is a receiver disclosed in Japanese Unexamined Patent Application Publication No. 11-55599 (Kawabata). According to the receiver disclosed by Kawabata, when the tuner of the receiver receives a receiver stop signal from a broadcasting station, the microcomputer calculates the time to turn the power supply next time based on the stop receiver signal. Next the time to turn on the power supply next time is set in the timer. Then, the receiver is supplied with the electric power from the power supply again after the lapse of a prescribed time.
However, according to the receiver disclosed by Kawabata, ON/OFF of the power supply is switched by inputting a time schedule from an external device. For this reason, in the case where the ON/OFF of the power supply is switched frequently, the signal for switching the ON/OFF of the power supply must be constantly sent to the receiver from the external device. That is, there is a problem that it is difficult for the receiver to switch the ON/OFF of the power supply frequently.